2001~2020年乌梁素海流域植被NPP时空变化及驱动因素分析

Spatiotemporal Variation Characteristics and Driving Factors of Vegetation NPP in the Ulansuhai Nur Basin from 2001 to 2020

植被净初级生产力(NPP)表征植物对生态系统碳的固定能力,是决定生态系统健康状态和可持续发展程度的关键指标,其时空变化及驱动因素对于揭示植被恢复状况和指导生态修复工作具有重要作用.基于2001~2020年MODIS17A3 NPP数据、土地利用和气象数据等,采用变异系数、Theil-Sen Median趋势分析及Mann-Kendall检验、Hurst指数和地理探测器等方法,探究了内蒙古乌梁素海流域植被NPP的时空变化特征及驱动因素.结果表明:①2001~2020年乌梁素海流域植被NPP整体呈波动上升趋势,平均值(以C计)为141.03 g·(m^(2)·a)^(-1),平均上升速率为2.33g·(m^(2)·a)^(-1);植被NPP具有明显的空间分异规律,整体上呈现西南高、东北低,河套平原高、沙地和山区低的特征;②NPP主要呈增长趋势,增长、减少和无变化区域的面积占比分别约为80%、3%和17%;NPP的平均变异系数为0.149,主要呈低波动变化和较低波动变化,面积占比约为51%;NPP未来变化趋势主要呈反持续性特征,面积占比约为75%.③土地利用、海拔、最高温和坡度是乌梁素海流域植被NPP变化的主导驱动因素,q值均在0.200以上.海拔∩相对湿度对乌梁素海流域植被NPP空间分异的解释力最大;土地利用与除夜间灯光外的其他因子对乌梁素海流域植被NPP空间分异的解释力均存在显著性差异.根据研究结果,未来应加强乌梁素海流域生态系统管理,实行严格的生态保护和修复政策,综合考虑气候、地形和人类活动等因素,因地制宜开展生态综合治理工作,以提升生态系统服务质量.

Vegetation net primary productivity(NPP)represents the ability of plants to fix ecosystem carbon,which is a key indicator to determine the health status and sustainable development of ecosystems.Its spatial and temporal changes and driving factors play an important role in revealing the status of vegetation restoration and guiding ecological restoration.Based on MODIS17A3 NPP data,land use,and meteorological data from 2001 to 2020,the temporal and spatial variation characteristics and driving factors of vegetation NPP in the Ulansuhai Nur Basin of Inner Mongolia were explored by using the methods of coefficient of variation,Theil-Sen Median trend analysis,Mann-Kendall significance test,Hurst index,and Geodetector.The results showed that:①From 2001 to 2020,the vegetation NPP in the Ulansuhai Nur Basin showed a fluctuating upward trend,with an average value(in terms of C)of 141.03 g·(m^(2)·a)^(-1)and an average increase rate of 2.33 g·(m^(2)·a)^(-1).The vegetation NPP had obvious spatial differentiation,which was characterized by high in the southwest and low in the northeast and high in Hetao Plain and low in sandy land and mountainous areas.②NPP mainly showed an increasing trend,and the area proportions of increasing,decreasing,and unchanged areas were approximately 80%,3%,and 17%,respectively.The average coefficient of variation of vegetation NPP was 0.149,which mainly showed low fluctuation change,and the area accounted for approximately 51%.The future change trend of NPP was mainly characterized by anti-persistence,with an area ratio of approximately 75%.③Land use,altitude,maximum temperature,and slope were the dominant driving factors of variation NPP change in the Ulansuhai Nur Basin,and the q values were all above 0.200.The interaction between altitude and relative humidity had the greatest explanatory power for the spatial differentiation of vegetation NPP in the Ulansuhai Nur Basin.There were significant differences in the explanatory power of land use and all factors except nighttime light to the spatial differentiation of vegetation NPP in the Ulansuhai Nur Basin.According to the research results,in the future,we should strengthen the ecosystem management of the Ulansuhai Nur Basin;continue to implement strict ecological protection and restoration policies;and comprehensively consider factors such as climate,topography,and human activities to carry out comprehensive ecological management according to local conditions to improve the quality of ecosystem services.